Sealing apparatus and methods of use

ABSTRACT

A system for treating an aneurysm comprises at least a first double-walled filling structure having an outer wall and an inner wall and the filling structure is adapted to be filled with a hardenable fluid filling medium so that the outer wall conforms to the inside surface of the aneurysm and the inner surface forms a generally tubular lumen to provide blood flow. The first filling structure comprises a sealing feature which forms a fluid seal between the filling structure and the aneurysm or an adjacent endograft when the filling structure is filled with the hardenable fluid filling medium, thereby minimizing or preventing blood flow downstream of the seal.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present application is a divisional of U.S. application Ser. No.12/478,225 filed Jun. 4, 2009 (now U.S. Pat. No. 8,945,199), which is anon-provisional of, and claims the benefit of priority under 35 U.S.C. §119(e) of U.S. Provisional Application No. 61/058,810 filed Jun. 4,2008; each of which the entire contents are incorporated herein byreference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates generally to medical systems and methodsfor treatment. More particularly, the present invention relates toapparatus and methods for treating aneurysms.

Aneurysms are enlargements or “bulges” in blood vessels which are oftenprone to rupture and which therefore present a serious risk to thepatient. Aneurysms may occur in any blood vessel but are of particularconcern when they occur in the cerebral vasculature or the patient'saorta.

The present invention is particularly concerned with aneurysms occurringin the aorta, particularly those referred to as aortic aneurysms.Abdominal aortic aneurysms (AAA's) are classified based on theirlocation within the aorta as well as their shape and complexity.Aneurysms which are found below the renal arteries are referred to asinfrarenal abdominal aortic aneurysms. Suprarenal abdominal aorticaneurysms occur above the renal arteries, while thoracic aorticaneurysms (TAA's) occur in the ascending, transverse, or descending partof the upper aorta.

Infrarenal aneurysms are the most common, representing about eightypercent (80%) of all aortic aneurysms. Suprarenal aneurysms are lesscommon, representing about 20% of the aortic aneurysms. Thoracic aorticaneurysms are the least common and often the most difficult to treat.

The most common form of aneurysm is “fusiform,” where the enlargementextends about the entire aortic circumference. Less commonly, theaneurysms may be characterized by a bulge on one side of the bloodvessel attached at a narrow neck. Thoracic aortic aneurysms are oftendissecting aneurysms caused by hemorrhagic separation in the aorticwall, usually within the medial layer. The most common treatment foreach of these types and forms of aneurysm is open surgical repair. Opensurgical repair is quite successful in patients who are otherwisereasonably healthy and free from significant co-morbidities. Such opensurgical procedures may be problematic, however, since access to theabdominal and thoracic aortas is difficult to obtain and because theaorta must be clamped off, placing significant strain on the patient'sheart.

Over the past decade, endoluminal grafts have come into widespread usefor the treatment of aortic aneurysm in patients who cannot undergo opensurgical procedures. In general, endoluminal repairs access the aneurysm“endoluminally” through either or both iliac arteries in the groin. Thegrafts, which typically have been fabric or membrane tubes supported andattached by various stent structures, are then implanted, typicallyrequiring several pieces or modules to be assembled in situ. Successfulendoluminal procedures have a much shorter recovery period than opensurgical procedures.

Present endoluminal aortic aneurysm repairs, however, suffer from anumber of limitations. For example, a significant number of endoluminalrepair patients experience leakage at the proximal juncture (attachmentpoint closest to the heart) within two years of the initial repairprocedure. While such leaks can often be fixed by further endoluminalprocedures, the need to have such follow-up treatments significantlyincreases cost and is certainly undesirable for the patient. A lesscommon but more serious problem has been graft migration. In instanceswhere the graft migrates or slips from its intended position, opensurgical repair is required. This is a particular problem since thepatients receiving the endoluminal grafts are often those who are notconsidered to be good surgical candidates.

Further shortcomings of the present endoluminal graft systems relate toboth deployment and configuration. For example, many of the commerciallyavailable endovascular systems are too large (above 12F) forpercutaneous introduction. Moreover, current devices often have anannular support frame that is stiff and difficult to deliver as well asunsuitable for treating many geometrically complex aneurysms,particularly infrarenal aneurysms with little space between the renalarteries and the upper end of the aneurysm, referred to as short-neck orno-neck aneurysms. Aneurysms having torturous geometries, are alsodifficult to treat.

In order to overcome some of the aforementioned challenges, the use ofendograft systems having a scaffold structure and a filling structurehas been proposed, such as in U.S. patent application Ser. No.11/413,460 (Attorney Docket No. 025925-001610US) filed Apr. 28, 2006,the entire contents of which are incorporated herein by reference. Thesesystems utilize a filling structure to help seal off and fill theaneurismal sac while creating a lumen for blood to traverse theaneurysm. Several references disclosing filling structures and which arethe subject of the commonly owned, copending applications are describedbelow. These systems may also include a stent-like scaffold which helpssupport the filling structure thereby further defining the lumen forblood flow. The filling structure may require a pre-filling step to helpunfurl the filling structure prior to filling it with the hardenablefilling material and an expandable balloon often is used to help supportthe endograft during filling and during hardening in order to ensureproper formation of a lumen for blood flow. Because the filling materialmay take some time to harden, the expanded balloon can occlude flow foran undesirable time. Additionally, even after filling and hardening offilling material in the filling structure, the aneurismal sac may not becompletely sealed off and blood can still flow into the sac. For thesereasons it would be desirable to provide alternative apparatus andmethods that create a better seal between the aneurismal sac and theendograft. It would also be desirable to provide apparatus and methodsthat help filling structures expand and conform to the aneurysm anatomy.Moreover, it would also be desirable for sealing apparatus and methodsto minimize or eliminate the need for a separate unfurling step as wellas minimizing the need to use an inflated balloon for support duringfilling and hardening that can obstruct blood flow. It would also bedesirable that the alternative apparatus have a low profile for ease ofdelivery and percutaneous introduction as well as flexibility to allowadvancement of the device through torturous vessels such as the iliacarteries. It would further be desirable that such devices canaccommodate a variety of different vessel and aneurysm anatomies. Atleast some of these objectives will be met by the inventions describedhereinbelow.

2. Description of the Background Art

U.S. Patent Publication No. 2006/0025853 describes a double-walledfilling structure for treating aortic and other aneurysms. Copending,commonly owned U.S. Patent Publication No. 2006/0212112, describes theuse of liners and extenders to anchor and seal such double-walledfilling structures within the aorta. The full disclosures of both thesepublications are incorporated herein by reference. PCT Publication No.WO 01/21108 describes expandable implants attached to a central graftfor filling aortic aneurysms. See also U.S. Pat. Nos. 5,330,528;5,534,024; 5,843,160; 6,168,592; 6,190,402; 6,312,462; 6,312,463; U.S.Patent Publications 2002/0045848; 2003/0014075; 2004/0204755;2005/0004660; and PCT Publication No. WO 02/102282.

BRIEF SUMMARY OF THE INVENTION

The present invention provides apparatus and methods for the treatmentof aneurysms, particularly aortic aneurysms including both abdominalaortic aneurysms (AAA) and thoracic aortic aneurysms (TAA).

In a first aspect of the present invention, a system for treating ananeurysm comprises at least a first double-walled filling structurehaving an outer wall and an inner wall and the filling structure isadapted to be filled with a hardenable fluid filling medium so that theouter wall conforms to the inside surface of the aneurysm and the innersurface forms a generally tubular lumen to provide blood flow. The firstfilling structure comprises a sealing feature which forms a fluid sealbetween the filling structure and the aneurysm or an adjacent endograftwhen the filling structure is filled with the hardenable fluid fillingmedium. This minimizes or prevents blood flow downstream of the seal.

The walls of the filling structure may comprise ePTFE and the seal maybe disposed upstream of the aneurysm, for example in the aneurysm neck.Sometimes the walls of the filling structure may be coated with anotherpolymer such as polyurethane. The tubular lumen may have a substantiallycircular cross-section and the first filling structure may comprise anelliptical cross-section when the filling structure is filled with thehardenable filling medium. The edges of the first filling structure maybe sealed together so that the filling structure can withstand a fillingpressure of up to 300 mm Hg above a patient's normal systolic bloodpressure without bursting. Some systems may also comprise a thrombogenicmaterial such as polyurethane, polycarbonate, polyester, ePTFE,polyolefin, parylene, gelatin and silicone. The thrombogenic materialmay be coupled with an outer surface of the first filling structure andit may be formed into one of sutures, felts, velours, weaves, knits,hydrogels, foams, coils, sheets and combinations thereof. Thethrombogenic material may also comprise a thrombogenic drug.

In some embodiments the first filling structure may include a main bodyhaving a main body width and the sealing feature may comprise a narrowneck region that is coupled with the main body. The narrow neck regionmay have a width that is less than the main body width. The width of thenarrow neck region may be approximately 2% to approximately 20% of themain body width. Sometimes the sealing feature may include a flatshoulder on an upper portion of the filling structure. Other embodimentsmay have a sealing feature which includes a tapered shoulder region onan upper portion of the filling structure.

Still, in other embodiments the first filling structure may comprise anupper layer of material having an upper layer width and a lower layer ofmaterial having a lower layer width that is wider than the upper layerwidth. The upper and lower layers are fixedly coupled together so as toform the sealing feature which comprises a substantially flat upperouter surface and an arcuate lower outer surface when the first fillingstructure is filled with hardenable filling medium. The first fillingstructure may comprise a D-shaped cross-section when filled withhardenable filling medium.

The sealing feature may comprise a tapered region in the tubular lumenwith the taper disposed near an upper portion of the first fillingstructure. The tapered region may flare inwardly from the upper portionof the first filling structure to a lower portion of the first fillingstructure. In other embodiments, the first filling structure maycomprise an upper layer of material and a lower layer of material,wherein at least a portion of the upper layer is fixedly coupled with atleast a portion of the lower layer of material which forms the sealingfeature. In this case, the sealing feature comprises an upper fillingregion and a lower filling region formed by the seal with the twofilling regions in fluid communication with one another. The upperfilling region may hold a smaller volume of filling medium than thelower filling region and the seal may be formed along a line. The linemay extend from an outer edge of the first filling structure inwardtowards the tubular lumen.

In other embodiments, the system may further comprise a seconddouble-walled filling structure having an outer wall and an inner wall,wherein the second filling structure is adapted to be filled with ahardenable fluid filling medium so that the outer wall conforms to theinside surface of the aneurysm and the inner surface forms a generallytubular lumen to provide blood flow. The second filling structure maycomprise a sealing feature which forms a fluid seal between the fillingstructure and the aneurysm or an adjacent endograft when the secondfilling structure is filled with the hardenable fluid filling medium.This minimizes or prevents blood flow downstream of the seal. Thesealing feature of the first double-walled filling structure maycomprise an outer surface having a first shape and the sealing featureof the second double-walled filling structure may comprise an outersurface having a second shape. The first and second shapes may becomplementary to one another. In some embodiments, the first and secondshapes comprise complementary tapers.

In still other embodiments, the sealing feature may comprise a foamfilled region of the first filling structure and the foam filled regionmay be discrete from the remainder of the first filling structure. Thediscrete foam filled region may be fluidly isolated from the regionfilled with the hardenable filling medium. In other embodiments, thesealing feature may comprise an arm in fluid communication with theregion filled with the hardenable filling medium. Alternatively, thesealing feature may comprise a slot that is substantially transverse toa longitudinal axis of the first double-walled filling structure. Theslot may at least partially bisect the first double-walled fillingstructure into two fillable sections. The foam may be substituted forany other material that provides the desired compliance to the foamfilled region, such as gels, suture material, etc.

Some embodiments may have a sealing feature which comprises a wingedregion that flares radially outward from the first double-walled fillingstructure. The winged region may comprise a tapered shoulder on an outersurface of the first double-walled filling structure. The sealingfeature may further comprise a tapered lower region in the tubular lumenwhich flares radially outward from an upper part to a lower part of thefirst filling structure. Sometimes the sealing feature may also comprisea restraining element that is disposed at least partially around thetubular lumen. The restraining element may be adapted to restrict radialexpansion of the tubular lumen to a predetermined size or shape.Sometimes the restraining element comprises a band extendingcircumferentially around the tubular lumen.

The sealing feature may comprise an enlarged head region and a taperedlower region on the first filling structure. The tapered region flaresradially outward as the distance from the head region increases. Thesealing feature may comprise a lower tubular cuff region coupled withthe first filling structure and a winged portion on the first fillingstructure. The sealing feature may also include an upper tubular cuffregion coupled with the first filling structure. Sometimes the sealingfeature includes a skeletal frame disposed in between the inner andouter walls of the first filling structure and the inner wall radiallyexpands inward as the first filling structure is filled with hardenablefilling material. Alternatively, the first filling structure may bedisposed on the inside surface of a radially expandable scaffold and thesealing feature may comprise a portion of the inner wall that is adaptedto radially expand inward to engage and seal against an adjacentendograft.

The sealing feature may comprise an angled bottom edge on the firstfilling structure. In some embodiments, the filling structure maycomprise a straight top edge and the angled bottom edge forms an acuteangle relative to the top edge. In other embodiments, the sealingfeature comprises a discrete filling compartment separate from thefilling space of the first double-walled filling structure and fluidlyuncoupled thereto. The discrete filling compartment may have arectangular shaped region and the hardenable filling medium may surroundthe discrete filling compartment. An elongate flexible filling tube maybe slidably engaged with the discrete filling compartment and thefilling space.

In other embodiments, the sealing feature may comprise a shoulder thatis disposed on a lower portion of the first filling structure. The firstfilling structure may have a main body width and the shoulder may have ashoulder width that is less than the main body width. The sealingfeature may comprise an undercut region in the first filling structurethat is adapted to expand outwardly when the first filling structure isfilled with hardenable filling material.

The sealing feature may include a plurality of filaments coupled withthe first filling structure and extending axially therefrom. Thesefilaments may include a thrombogenic material. The thrombogenic materialmay also be a cape that is disposed at least partially over the firstfilling structure and coupled thereto. The sealing feature could also bea thrombogenic annular ring that is disposed at least partially aroundthe first filling structure. Other sealing features may include aplurality of flanges that are coupled with the first filling structure.The flanges may have a width that progressively decreases relative to anadjacent flange. Also, the flanges may have a thickness thatprogressively decreases relative to an adjacent flange.

In still other embodiments the sealing feature may comprise a skeletalframe that is coupled with the first filling structure. The skeletalframe may comprise a plurality of self-expanding struts that are adaptedto radially expand outward along with the outer wall of the firstfilling structure. The skeletal frame may comprise a wire-like helicallyshaped filament made from a material such as nitinol.

The scaling feature may also comprise an upper and a lower tubularshaped cuff that is coupled with the first filling structure. At leastone of the upper or lower cuffs may comprise a reinforced region. Thereinforced region may comprise a wire-like frame and sometimes the upperand lower reinforced cuffs may be coupled together with a plurality ofstruts.

In still other embodiments, the sealing feature may comprise a pair offillable legs that are coupled with the first filling structure. Thesealing feature may comprise a first region of the first fillingstructure having a first compliance and a second region of the firstfilling structure having a second compliance different than the firstcompliance. One of these regions may be embossed and another region mayremain unembossed.

The system may further comprise a delivery catheter that has anexpandable tubular support such as a balloon, which can be positionedwithin the tubular lumen to carry the double-walled filling structure.The system may also comprise a scaffold that is radially expandable froma collapsed configuration to an expanded configuration. A filling portthat is fluidly coupled with the filling structure may also be includedin the system. The filling port may be an elastomeric plug, and may beadapted to receive the hardenable filling medium and also provides aseal to prevent leakage thereof. The filling port may be substantiallycontained within the inner lumen of the filling structure when thefilling structure is filled with the hardenable filling medium.

In another embodiment of the invention, a system for treating ananeurysm comprises at least a first double-walled filling structurehaving an outer wall and an inner wall. The filling structure is adaptedto be filled with a hardenable fluid filling medium so that the outerwall conforms to the inside surface of the aneurysm and the innersurface forms a generally tubular lumen to provide blood flow. Thesystem also includes a filling port that is substantially containedwithin the generally tubular lumen of the filling structure when thefilling structure is filled with the hardenable fluid filling medium. Afirst end of the generally tubular lumen may comprise an invaginatedtapered portion that flares radially outward. A second end of thetubular lumen may comprise an invaginated tapered portion that flaresradially outward. The second end may be opposite of the first end. Thefirst filling structure may comprise a sealing feature that forms afluid seal between the filling structure and the aneurysm or an adjacentendograft when the filling structure is filled with the hardenable fluidfilling medium. This reduces or prevents blood flow downstream of theseal. The sealing feature may comprise a tapered shoulder region on atleast one end of the filling structure. The outer wall of the fillingstructure may be invaginated into the filling structure thereby forminga convex exterior surface on one end of the filling structure when thefilling structure is filled with the hardenable fluid filling medium. Aconvex exterior surface may also be similarly formed on a second end ofthe filling structure opposite the first end. Either convex exteriorsurface may taper radially inwardly to merge with the tubular lumen.

These and other embodiments are described in further detail in thefollowing description related to the appended drawing figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates the anatomy of an infrarenal abdominal aorticaneurysm.

FIG. 2 illustrates a single prosthesis system comprising a fillingstructure mounted over a delivery catheter.

FIG. 3 illustrates a pair of prostheses for delivery to an aneurysm,where each prosthesis comprises a filling structure mounted on adelivery catheter.

FIGS. 4A-4F illustrate use of the filling structures of the prosthesissystem in FIG. 3 for treating an aortic aneurysm.

FIGS. 4G-4H illustrate the placement of scaffolds into the adjacenttubular lumens of the two filling structures of the prostheses of FIGS.4A-4F.

FIGS. 4H-1 and 4H-2 are cross-sectional views taken along line 4H1-4H1or 4H2-4H2 in FIG. 4H.

FIGS. 5A-5B illustrate one embodiment of a double-walled fillingstructure.

FIGS. 5C-5E illustrate an exemplary method of fabricating the fillingstructure in FIGS. 5A-5B.

FIG. 5F illustrates a filling port.

FIGS. 6A-18 illustrate alternative embodiments of a double-walledfilling structure.

FIGS. 19A-20 illustrate filling structures with regions of differentcompliance.

FIG. 21 illustrates a system for treating an aneurysm having threeendografts.

FIGS. 22-26B illustrate various embodiments of filling structures thatmay be used in the endograft system of FIG. 21.

FIGS. 27-29 illustrate various thrombogenic features used to help createa seal.

FIGS. 30A-30C illustrate several embodiments of resilient frames coupledwith the filling structure.

FIGS. 31A-32D illustrate various reinforced regions and patterns thatmay be used on a filling structure.

FIGS. 33A-33B illustrate another embodiment of a filling structure.

FIGS. 34A-34D illustrate the use of multiple filling structures stackedtogether.

FIGS. 35A-35B illustrate an alternative embodiment of a double-walledfilling structure.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to FIG. 1, the anatomy of an infrarenal abdominal aorticaneurysm comprises the thoracic aorta (TA) having renal arteries (RA) atits distal end above the iliac arteries (IA). The abdominal aorticaneurysm (AAA) typically forms between the renal arteries (RA) and theiliac arteries (IA) and may have regions of mural thrombus (T) overportions of its inner surface (S).

FIG. 2 illustrates a single endograft system comprising a fillingstructure mounted over a delivery catheter. A system 10 constructed inaccordance with the principles of the present invention for delivering adouble-walled filling structure 12 to an aneurysm includes the fillingstructure and a delivery catheter 14 having an expandable element 16,typically an inflatable balloon, at its distal end. The catheter 14 willcomprise a guidewire lumen 18, a balloon inflation lumen (notillustrated) or other structure for expanding other expandablecomponents, and a filling tube 20 for delivering a filling medium ormaterial to an internal space 22 of the double-walled filling structure12. The internal space 22 is defined between an outer wall 24 and innerwall 26 of the filling structure. Upon inflation with the fillingmaterial or medium, the outer wall will expand radially outwardly, asshown in broken line, as will the inner wall 26, also shown in brokenline. Expansion of the inner wall 26 defines an internal lumen 28. Theexpandable balloon or other structure 16 will be expandable to supportan inner surface of the lumen 28, as also in broken line in FIG. 1. Asingle endograft system such as that seen in FIG. 1 may be used to treatan aneurysm as disclosed in U.S. patent application Ser. No. 11/413,460(Attorney Docket No. 025925-001610US), the entire contents of which areincorporate herein by reference.

In preferred embodiments, a system comprising two endografts may be usedto treat an aneurysm, such as the system seen in FIG. 3. A systemcomprising such a pair of filling structures includes a first fillingstructure 112 and a second filling structure 212. Each of the fillingstructures 112 and 212 are mounted on delivery catheters 114 and 214,respectively. The components of the filling structures 112 and 212 anddelivery catheters 114 and 214 are generally the same as those describedpreviously with respect to the single filling structure system 10 ofFIG. 2. Corresponding parts of each of the fillings systems 112 and 212will be given identical numbers with either the 100 base number or 200base number. A principal difference between the filling structures 112and 212, on the one hand, and the filling structure 12 of FIG. 2 is thatthe pair of filling structures will generally have asymmetricconfigurations which are meant to be positioned adjacent to each otherwithin the aneurismal space and to jointly fill that space, as will bedescribed in greater detail below.

In treating an infrarenal abdominal aortic aneurysm using the pair offilling structures 112 and 212 illustrated in FIG. 3, a pair ofguidewires (GW) will first be introduced, one from each of the iliacarteries (IA), as seen in FIG. 4A. The first delivery catheter 114 willthen be positioned over one of the guidewires to position thedouble-walled filling structure 112 across the aortic aneurysm (AAA), asillustrated in FIG. 4B. The second delivery catheter 214 is thendelivered over the other guidewire (GW) to position the second fillingstructure 212 adjacent to the first structure 112 within the aneurysm(AAA), as illustrated in FIG. 4C. Typically, one of the fillingstructures and associated balloons will be expanded first, followed bythe other of the filling structures and balloon, as illustrated in FIG.4D where the filling structure 112 and balloon 116 are inflated to fillgenerally half of the aneurismal volume, as illustrated in FIG. 4D.Filling can generally be carried out as described for one fillingstructure in U.S. patent application Ser. No. 11/413,460 (AttorneyDocket No. 025925-001610US) which has been previously incorporatedherein by reference, except of course that the filling structure 112will be expanded to occupy only about one-half of the aneurismal volume.After the first filling structure 112 has been filled, the secondfilling structure 212 may be filled, as illustrated in FIG. 4E. In otherprotocols the two filling structures may be filled simultaneously. Theupper ends of the balloons 116 and 216 will conform the tubular lumensof the filling structures against the walls of the aorta as well asagainst each other, while the lower ends of the balloons 116 and 216will conform the tubular lumens into the respective iliac (IA).

After filling the filling structures 112 and 212 as illustrated in FIG.4E, the filling materials or medium will be cured or otherwise hardened,and the delivery catheters 114 and removed, respectively. The hardenedfilling structures will then provide a pair of tubular lumens openingfrom the aorta beneath the renal arteries to the right and left iliacarteries, as shown in broken line in FIG. 4F. The ability of the fillingstructures 112 and 212 to conform to the inner surface (S) of theaneurysm, as shown in FIG. 4F, helps the structures to remainimmobilized within the aneurysm with little or no migration.Immobilization of the filling structures 112 and 114 may be furtherenhanced by providing any of the surface features described in U.S.patent application Ser. No. 11/413,460 (Attorney Docket No.025925-001610US), previously incorporated herein by reference.

As with the single filling structure embodiments, the double fillingstructure embodiments will include at least one separate scaffolddeployed within each of the tubular blood flow lumens. The scaffoldswill generally be stent-like or graft-like vascular structures and willbe deployed within the tubular lumens using balloon or other expansioncatheters (in the case of malleable or balloon-expandable scaffolds) orusing constraining sheaths (in the case of self-expanding scaffolds).

Referring in particular to FIG. 4G, the first scaffold 250 may be placedin the tubular lumen of the first filling structure 112 while a secondscaffold 252 may be placed in the tubular lumen of the second fillingstructure 212. As illustrated, the scaffolds are stent-like structureswhich extend into the iliac arteries IA at the lower end of the fillingstructures. The scaffolds 250, 252 may also be deployed simultaneouslywith the filling structures 112, 212.

Referring now to FIG. 4H, first and second scaffolds 254 and 256 mayextend upwardly on the aortic side of the first and second fillingstructures 112 and 212. When the separate stent or other scaffoldstructures extend into the thoracic aorta TA, it will usually bedesirable that they be expanded so that they conform to each other alonga plane or region of contact. For example, as shown in FIG. 4H-1, theupper ends of the scaffolds 254 and 256 may be formed preferentially tohave D-shaped cross-sections when expanded. Thus, flat faces 258 and 260will engage each other with the remaining portion of the stentconforming to the inner wall of the aorta. In this way, most of thecross-sectional area of the aorta will be covered with the stent, thusenhancing blood flow through the filling structures. Alternatively, asshown in FIG. 4H-2, the upper regions of the scaffolds 254 and 256 maybe cut or otherwise modified to form open C-shaped cross-sections. Insuch cases, the expanded scaffolds can be arranged so that the C-shapedregions engage each other to form a continuous ring structure about theinner wall of the aorta. The open C-shaped regions will transition intoa tubular region as the scaffolds enter the tubular lumens of thefilling structures 112 and 212. In either of these embodiments, thescaffolds 254 and 256 may be partially or fully covered with a membraneor graft material and such coverings may extend partially or fully overthe portion of the scaffold that extends into the adjacent blood vessel.

Various modifications of the protocols described above will be withinthe scope of the present invention. For example, while the scaffoldshave been shown as being delivered after deployment of the fillingstructure(s), it will also be possible to deliver the scaffoldssimultaneously with or prior to deployment of the filling structures.Moreover, the scaffolds could be delivered on the same deliverycatheter(s) used to deliver and/or shape the filling structures. Thescaffolds could then be expanded at the same time as filling the fillingstructure or even prior to filling the filling structure. Additionaldetails on these embodiments are disclosed in U.S. patent applicationSer. No. 11/413,460 (Attorney Docket No. 025925-001610US), previouslyincorporated herein by reference.

The filling structure used in FIGS. 4A-4H are more fully described inFIGS. 5A-5E. FIG. 5A illustrates the double-walled filling structureseparated from the delivery catheter and scaffold. In FIG. 5A, the outerwall 502 is the portion of the filling structure which expands intoengagement with the aneurysm wall when filled with filling material andinner wall forms lumen 504 in which blood traverses the aneurysm. Afilling tab FT is coupled with the filling structure and acts as a valveto allow filling of the filling structure. FIG. 5B shows an end view ofthe filling structure with an oval or elliptical-shaped outer wall 502and a round inner lumen 504. The walls of the filling structure arepreferably made from ePTFE with a polyurethane inner lining whichprevents extravasation of the filling material through the pores of theePTFE. Other polymers or fabrics may also be used such as Dacronpolyester. Any of the filling structure embodiments in this disclosuremay use these materials.

The filling structure of FIGS. 5A-5B may be fabricated from two sheetsof polymer as seen in FIGS. 5C and 5D. In FIG. 5C, an upper sheet is diecut from ePTFE and has an upper flat pan section 508 a and a lowerhandle section 510 a. In FIG. 5D, a second sheet is also die cut fromePTFE and also has an upper pan section 508 b and a lower handle section510 b. The upper and lower sheets are substantially the same size. Thetwo sheets are then placed on top of one another and the edges are thensealed together around most of the perimeter, as seen by seam 512 inFIG. 5E. The lower handle section is then invaginated and pulled throughthe flat pan section as indicated by arrow 514. The unsealed portionsare then sealed. Sealing may be accomplished using a hot wire, impulsesealing. RF heat sealing or laser welding. This forms the inner lumen ofthe filling structure, as indicated by dotted lines in FIG. 5A. Afilling tube 506 may be used to allow filling of the filling structureas seen in FIG. 5A or a filling port 516 may be used as illustrated inFIG. 5F. The filling port 516 may be an elastomeric plug such as latexor polymer that allows a needle or other tube to penetrate the fillingport and that self seals when the needle or tube is withdrawn. Thismethod of fabrication generally applies to any of the embodimentsdisclosed herein. Other fabrication methods include inverting a tubularextrusion and sealing the ends which is advantageous since it minimizesseams. Also, in some embodiments, the filling structure may be composedof separate components that are joined together. For example, thetubular lumen section may be formed separately and then coupled with themain body of the filling portion.

As previously discussed, these filling structures show promise in thetreatment of aneurysms as they help seal the aneurysm and also they helpfix an endograft system in place thereby minimizing the possibility ofmigration. However, the filling structures can still leak. Therefore,other filling structure configurations and features are disclosed hereinwhich may provide better sealing.

In FIG. 6A, the filling structure has an outer wall W and an inner wallforms the lumen L. This embodiment also includes a flat shoulder 608 anda narrow neck region 610 which may accommodate aneurysm anatomies betterand therefore provide better sealing. FIG. 6B shows and end view of thefilling structure in FIG. 6A. The neck region may have a width any size,but in preferred embodiments, the width of the neck region 610 isapproximately 2% to approximately 20% of the filling structure widthmeasured at it's widest point. FIGS. 7A-7B show another embodiment of afilling structure. In FIG. 7A, a double-walled filling structureincludes a tapered upper portion 620 which provides a flat surfaceagainst which a seal may be made. FIG. 7B shows an end view of thefilling structure seen in FIG. 7A which has a generally oval shape whenfilled with filling material and the lumen L is generally round.

FIGS. 8A-8B show another embodiment of a filling structure. In FIG. 8A,a first layer of material is welded to a second layer of material thatis wider than the first. This results in one side of the fillingstructure having more material than the opposite side. Therefore, oneside of the outer wall W will have a substantially flat section 626 andthe opposite side will be arcuate 630 with a straight section 628joining the two sections together. The end view of the filling structurewill be D-shaped as seen in FIG. 8B.

Still another filling structure embodiment is seen in FIGS. 9A-9B. InFIG. 9A the inner wall of the filling structure forms lumen L. Lumen Lincludes a straight tubular section and a tapered portion 640 near anupper portion of the filling structure. The tapered portion 640 flaresradially outward. FIG. 9B shows an end view of the filling structureseen in FIG. 9A. In FIG. 9B, outer wall W forms a round or oval shapeand lumen L is generally round.

FIGS. 10A-10B illustrate the use of additional seals in the fillingstructure to define additional filling regions. In FIG. 10A, the twolayers of material are sealed together along a line 644 forming a pocket646 which is fillable with the hardenable filling material. In thisembodiment, the seal 644 is seen running across both the left and righthalves of the filling structure and in a direction generally transverseto the longitudinal axis of the filling structure. The length of thescal, number of seals and angle of the seal relative to the fillingstructure longitudinal axis may be varied. Also, in this embodiment, thepocket 646 is still in fluid communication with the main fillable regionof the filling structure. FIG. 10B illustrates an end view of thefilling structure seen in FIG. 10A.

In FIG. 11, two filling structures are used to complement one anotherand help for a seal. In FIG. 11, a first filling structure has an outerwall with a taper 652 and a generally tubular lumen L. A second fillingstructure has an outer wall W with a taper 654 that is complementary tothe first taper 652, therefore the two filling structures will engageone another where the two tapers meet. Because the two tapers arecomplementary with one another, they will be flush against one another.The use of two filling structures may be used when two endograft systemsare deployed in an aneurysm, such as in FIGS. 4A-4G above.

FIG. 12 shows a foam filled region 660 near an upper portion of thefilling structure. The foam filled region 660 is separated from theremainder of the fillable space by a seal 662 which may be made by heatsealing, bonding or other attachment methods known in the art. The foamfilled region provides a compliant end that allows the filling structureto conform to the aneurysm anatomy thereby helping create a seal.

FIG. 13 shows an alternative embodiment of a filling structure having aflexible arm coupled with the filling structure. A slot 668 separatesthe arm 666 from the main body of the filling structure, although achannel 670 fluidly couples the arm 666 with the main body of thefilling structure. Therefore, as the filling structure is filled withhardenable medium, the arm 666 will also fill up. The arm is flexibleand therefore will flex and fit into various aneurysms spaces therebycreating the seal.

FIG. 14 illustrates an angled filling structure. In FIG. 14, a bottomedge 680 of the filling structure is angled relative to the top edge682. In this embodiment, the bottom edge forms an acute angle relativeto the top edge 682 although the angle may be adjusted to accommodatedifferent aneurysm anatomies.

FIG. 15 illustrates the use of two filling regions in the fillingstructure. In FIG. 15, the filling structure has a main filling region688 and a separate, discrete filling region near a top of the fillingstructure. A filling tab FT is fluidly coupled with both fillableregions 686, 688, thus a filling tube may be slidably received by theupper filling region 686. After this region is filled, the filling tubeis retracted out of the upper filling tab and into the lower filling tabso that the main filling region can then be filled. The upper fillingregion may be created by scaling a region off from the main body of thefilling structure. This two stage filling process may allow the fillingstructure to create a better seal with the aneurysm.

FIG. 16 illustrates still another embodiment of a double-walled fillingstructure. In FIG. 16, the filling structure comprises a wide main bodysection 704 and a narrow neck region 702 on an upper end of the fillingstructure. A lower end of the filling structure has an annular flange706 that has a width less than the main body section 704. This helpsprevent or minimize pinching in the lower end of the filling structureand may help the filling structure accommodate various aneurysmanatomies.

FIG. 17 illustrates another embodiment of a double-walled fillingstructure. In FIG. 17, the filling structure has a wide main bodysection 728, a shoulder region 722 and a narrow neck region 720.Additionally, a concave bottom region 724 of the filling structure mayexpand outward when filled as indicated by dotted line 726.

FIG. 18 shows another filling structure embodiment having multipleannular flanges. In FIG. 18, the filling structure comprises a wide mainbody section 742 and a tapered lower region 744. The main body sectionhas a tapered shoulder region 752 which transitions into a region ofmultiple annular flanges. A first annular flange 746 is followed by twoadditional annular flanges 748, 750. The width and thickness of eachflange progressively decreases such that flange 746 is the widest andthickest while flange 750 is the thinnest. The multiple flanges helpcreate a seal at one end of the filling structure by minimizing pinchpoints.

FIGS. 19A-19B illustrate how the compliance of the filling structure maybe modified to affect how it expands. In FIG. 19A, the wall forming theinner lumen L may be made from a material having one compliance and thewall forming the outer wall W may be made from a material having greatercompliance. Thus, when the filling structure is filled with thehardenable filling material, the outer wall will preferentially radiallyexpand outward before the inner lumen wall. Thus, the lumen will remainrelatively unchanged during filling and the outer wall will conform tothe aneurysm. In FIG. 19B, the upper half of the outer wall of thefilling structure is fabricated from a material more compliant relativeto the lower half of the filling structure. Thus, the upper outer half762 will radially expand more than the lower half during filling. Onewill appreciate that compliance of the filling structure walls may bevaried to obtain desired expansion characteristics. Instead of usingdifferent materials to control filling structure compliance, surfacemodification may be used to alter a material's compliance. For example,in FIG. 20, an upper portion 770 of a filling structure has beenembossed while a lower portion 772 remains unembossed. Embossing thematerial alters material characteristics such as compliance. In the caseof expanded polytetrafluorinated ethylene (ePTFE), embossing increasesmaterial compliance so region 770 will have a greater compliance andexpand more than the unembossed region 772.

While most of the filling structure embodiments disclosed above aredescribed as being used when two endograft systems are deployed (e.g.FIG. 3) to treat an aneurysm, the embodiments described above may alsobe used in other endograft systems as well. For example, in some cases,it may be desirable to use a three piece endograft system to treat ananeurysm, such as in FIG. 21. In FIG. 21, a first docking scaffold 790is deployed in the neck of the aneurysm AAA and an optional fillingstructure 792 may be used to seal the neck region off from blood flow.Two leg extension scaffolds 796 and 798 are then advanced an expanded atleast partially within the docking scaffold 790. The leg scaffolds 796and 798 may also have optional filling structures 794, 799 which may beexpanded with hardenable filling material to fill the aneurismal space.Additional details on the three piece endograft system is disclosed inU.S. Provisional Patent Application No. 61/052,059 (Attorney Docket No.025925-002800US), the entire contents of which are incorporated hereinby reference. The filling structures previously described may thereforebe used in conjunction with the docking scaffold or either leg extensionscaffold. Additional filling structure embodiments which may be used inthe three piece docking system or the two piece system previouslydescribed are discussed in greater detail below.

FIG. 22 shows an embodiment of a filling structure having two legs 802,804. In FIG. 22, the main body 806 of the filing structure may becoupled with the docking scaffold to help seal at the neck of theaneurysm. Two leg regions 802, 804 help to seal around the leg extensionscaffolds that are received by the docking scaffold. FIG. 23 showsanother embodiment of a filling structure which may be used inconjunction with a docking scaffold. In FIG. 23, the filling structurehas a main body region 812 with an enlarged head region 810 and atapered lower region 814. The enlarged head region 810 and the taperedlower region help seal the docking scaffold around the neck of theaneurysm. FIGS. 24A-24C illustrate other embodiments which may be usedwith the docking scaffold. For example, in FIG. 24A a filling structurehas a main body portion 824 with a tapered shoulder 822 and a narrowneck region 820. The inner lumen L in the embodiment of FIG. 24A issubstantially tubular and has a constant diameter. In FIG. 24B, thefilling structure has generally the same shape as in FIG. 24A except inthis embodiment, the lumen L is tapered outwardly 826 near a lower endof the filling structure. The embodiment of FIG. 24C is also similar tothat of FIG. 24A but also has a modified lumen L. In FIG. 24C, thefilling structure lumen L has a lower portion that is constrained 828 inorder to limit its expansion. The constraint 828 may be a band or corsetcoupled with the inner wall, or a low compliance material may be used inthat region to limit expansion of the lumen L.

FIGS. 25A-25C illustrate still other embodiments of filling structureswhich may be used with the docking scaffold. In FIG. 25A, the fillingstructure comprises a main body section 840 with a tapered shoulder 842that transitions to a narrow neck region 844. FIG. 25B is similar to theembodiment of FIG. 25A except that both ends of the filling structurehave a narrow neck region 844, 848 coupled with the main body of thefilling structure. A flat or tapered shoulder region 846 may couple thenarrow neck region 844, 848 with the main body of the filling structure.FIG. 25C shows another variation of the embodiment in FIG. 25A. In FIG.25C, the filling structure has narrow neck regions 844, 848 coupled tothe main body of the filling structure. A tapered shoulder region 842couples the upper narrow neck region 844 with the filling structure mainbody and a flat lower shoulder 849 couples the lower narrow neck region848 with the main body of the filling structure.

The previous embodiments generally are disposed over a scaffoldstructure and radially expand outward to seal against the aneurysm wall.In FIGS. 26A-26B, a filling structure is used to fill the internal spaceof the docking scaffold. FIG. 26A illustrates a top view of a dockingscaffold. In FIG. 26A, a double-walled filling structure 862 is coupledto the internal surface of the docking scaffold 860. Two leg extensionscaffolds 864 are slidably received by the docking scaffold 860. In FIG.26B, the filling structure 862 is filled with a hardenable fillingmedium. The external wall of the filling structure 862 radially expandsoutward to engage and seal against the inner surface of the dockingscaffold 860. The inner wall of the filling structure 862 radiallyexpands inward to seal around the leg extension scaffolds 864.

The embodiments described above generally rely on radial expansion of afilling structure to form a seal. The use of thrombogenic materials incombination with a filling structure enhances the resulting seal. InFIG. 27, the filling structure has a plurality of filament-like hairs880 coupled to an upper portion of the filling structure. These hairs880 may be made of any thrombogenic material such as those disclosedherein or other materials known in the art. Additionally, the hairs 880may be coupled with a thrombogenic agent to further cause clotting. Thehairs 880 cause blood to clot thereby further sealing the aneurysm. Thehairs 880 may be glued, bonded, welded, heat sealed, sintered, sutured,electrospun, sprayed, vapor deposited, drape coated, press fit orotherwise attached to the filling structure. Exemplary materials forhairs 880 include but are not limited to polyurethanes, polycarbonates,polyesters such as Dacron, ePTFE, polyolefins, parylenes, gelatins,silicones, etc. The hair-like structures 880 may be formed into sutures,felts, velours, weaves, knits, hyodrogels, foams, embolization coils orsheets that are attached to the filling structure. FIG. 28 shows analternative embodiment of a filling structure having a thrombogenicmaterial attached thereto. In FIG. 28, a cape 882 is attached to thefilling structure. The cape may drape over all or a portion of thefilling structure and is fabricated from any of the materials disclosedherein. Because the cape is thin and flexible it will fit into the spacebetween the filling structure and the aneurysm wall and will help form ablood clot which further creates a seal. The cape 882 may take any shapeand may be attached to the filling structure using any of the previouslydescribed methods. FIG. 29 illustrates yet another embodiment of afilling structure with a thrombogenic material attached thereto. In FIG.29, an annular cuff 884 is coupled with a neck region of the fillingstructure. The cuff may be a Dacron cuff or it may be any material thatis known to be thrombogenic and it is attached to the filling structureusing techniques known to those of skill in the art. The cuff helps forma seal by causing thrombosis in the neck region of the fillingstructure. A cape structure having multiple lobes 1002 may also be usedto heal seal the aneurysm as shown in FIG. 33A. The lobes 1002 may befillable or not. If fillable, as seen in FIG. 33B, the lobes have a lowprofile prior to filling and a larger profile after filling as seen inFIG. 33A.

Still another embodiment of a filling structure is one that is seen inFIGS. 34A-34D. In FIG. 34A, multiple filling cylinders 1006, 1008, 1009are stacked inside one another to create a tapered or stepped fillingstructure as seen in FIG. 34C. FIG. 34C shows an alternative embodimentof a stacked filling structure having three cylinders 1010, 1012 and1014. FIG. 34D shows the cylinders of FIG. 34B after they have beenstacked together.

Another filling structure embodiment is seen in FIGS. 35A-35B. In FIG.35A the inner wall of the filling structure forms lumen 3500. Lumen 3500includes a straight tubular section 3501 and tapered portions 3502 and3503 near the ends of the filling structure. The tapered portions 3502and 3503 flare radially outward. Fill port 3504 is recessed into thetapered part of lumen 3503. This substantially prevents the fill portfrom contacting the aneurysm wall once the filling structure is filled.FIG. 35B shows an end view of the filling structure seen in FIG. 35A. InFIG. 35B, outer wall 3505 forms a round or oval shape and lumen 3500 isgenerally round. Additionally, outer wall 3505 is invaginated inwardlyto form a convex end rim. The opposite end may also be similarly formed.Fill port 3504 is situated within the tapered part of lumen 3500. Infurther alternative embodiments, the fill port may be located at eitherend of the fill structure, or may be exposed to contact the aneurysmwall. The cross-sectional shape at each end depends on the rate of taperof the corresponding tapered portions 3502 and 3503, becoming more roundas the ratio of length to width of the tapered portion increases. Thefilling structure may also comprise any of the sealing or other featuresdisclosed herein, such as a tapered shoulder illustrated in FIG. 7A.

In addition to filling structures and thrombogenic materials, aresilient spring-like frame or skeleton may be used to help radiallyexpand the filling structure into engagement with the aneurysm walls,thereby further enhancing the seal. For example, in FIG. 30A, thefilling structure comprises a plurality of elongate struts 902 or ribsthat are coupled with the filling structure. The struts 902 are biasedto flex radially outward, therefore after a constraint is released, thestruts will bow radially outward, forcing the filling structure to alsoexpand outward. FIG. 30B illustrates another embodiment where theresilient frame comprises a helical coil 904 and FIG. 30C illustrateshow the resilient frame may comprise struts which are transverse to thelongitudinal axis of the filling structure. The spring-like frame may bemade from any number of resilient metals such as stainless steel,nitinol or resilient polymers. The frame may be coupled to the inside oroutside surface of the filling structure, or it may be embedded inbetween the inner and outer filling structure walls.

Reinforcing the ends of the filling structures may also provide a betterseal since the reinforced region and/or lumen L will be rigid and cannotcollapse. FIGS. 31A-31C illustrate exemplary embodiments of reinforcedfilling structures. In FIG. 31A, the filling structure comprises narrowneck regions 912, 914 on both ends of the main body. One of the narrowneck regions 912 is reinforced with a frame to provide additionalstiffness in that region. The opposite narrow neck region 914 is shownunreinforced although it may also be reinforced. FIG. 31B illustratesreinforcement 916 along the entire filling structure longitudinal axis.FIG. 31C illustrates reinforcement on opposite ends 918, 920 of thefilling structure with connector struts 922 joining both reinforced ends918, 920. The reinforced areas may be metal, polymers or combinationsthereof. Various reinforcing patterns may be used such as those wellknown in the stent and stent-graft arts. For example, the reinforcedareas may have sine wave like patterns 932 as seen in FIG. 32A, diamondshapes 934 as in FIG. 32B, weaves 936 as in FIG. 32C or helical coils938 as in FIG. 32D. Many other geometries may also be used.

A number of embodiments of filling structure have been disclosed. Anycombination of these embodiments may also be made or substituted withone another. While use of the filling structures may have been describedwith respect to a two piece or a three piece endograft system, one ofskill in the art will appreciate that any filling structure may be usedin any endograft system. Additional features such as thrombogenicmaterials, thrombogenic agents, radially expanding frames and reinforcedregions have also been discussed. Any of these features may also be usedin combination with any of the filling structures.

A number of thrombogenic materials have also been disclosed such aspolyurethanes, polycarbonates, polyesters, ePTFE, polyolefins, parylene,gelatin, silicone, etc. Any of these materials may be used as thethrombogenic material and these materials may be formed into any numberof configurations such as sutures, felts, velours, weaves, knits,hydrogels, foams, embolization coils or sheets. Attachment methodsinclude but are not limited to gluing, heat sealing, welding, sintering,suturing/sowing, electrospinning, spraying, vapor deposition or drapecoating. The thrombogenic materials may be fabricated as a part of thefilling structure or they may be introduced during deployment of thefilling structure.

In addition to using thrombogenic materials, the surfaces of the fillingstructure may be modified in order to provide various materialproperties. For example, the surface may be textured, dimpled, etc. inorder to provide a surface that helps provide the desired amount ofthrombogenicity. Furthermore, the preferred embodiments have beendisclosed as being composed of ePTFE with an inner layer ofpolyurethane. Other materials may be used as the filling structure basematerial and a second or third or even more layers of other materialsmay be coupled to the base layer in order to provide the desiredmaterial characteristics of the filling structure. Specific regions ofthe filling structure may also be modified with a material or drug toprovide a desired effect, for example, a portion of the fillingstructure may be modified to be thrombogenic to help create a seal whileother regions remain unmodified or modified to have a different effect.Other materials or therapeutic agents like heparin may also be appliedto the surface of the tubular lumen to minimize thrombogenicity, or topromote healing and endothelialization as blood flows therethrough.

Filling materials may be any one or combination of materials that mayfill the filling structure and be hardened in situ. Examples of fillingmaterials include polyethylene glycol (PEG), silicones, etc. One ofskill in the art will appreciate that any of the features disclosedherein may be substituted or combined with any of the embodimentsdescribed herein. Moreover, in this disclosure the filling structure isreferred to as having an inner wall and an outer wall that may be filledand that can withstand pressures of approximately from about 30 mm Hg toabout 300 mm Hg above normal systolic blood pressure. One willappreciate the filling structure may also have multiple layers. Forexample, as disclosed, often the filling structure comprises an ePTFElayer with a coating of polyurethane thereover. Additional layers withother materials may similarly be used in order to control the materialproperties such as porosity and compliance. Therapeutic agents may alsobe coupled to the filling structure such as a thrombogenic agent on theoutside of the filling structure.

While the above is a complete description of the preferred embodimentsof the invention, various alternatives, modifications, and equivalentsmay be used. Therefore, the above description should not be taken aslimiting in scope of the invention which is defined by the appendedclaims.

What is claimed is:
 1. A system for treating an aneurysm, said systemcomprising: at least a first double-walled filling structure having anouter wall and an inner wall, wherein the filling structure is adaptedto be filled with a hardenable fluid filling medium so that the outerwall conforms to the inside surface of the aneurysm and the innersurface forms a generally tubular lumen to provide blood flow; and asealing feature, the sealing feature forming a fluid seal between thefilling structure and the aneurysm or an adjacent endograft when thefilling structure is filled with the hardenable fluid filling medium,thereby minimizing or preventing blood flow downstream of the seal. 2.The system of claim 1, wherein the sealing feature is disposed in a neckof the aneurysm and/or disposed upstream of the aneurysm.
 3. The systemof claim 1, wherein the sealing feature comprises an annular cuffdisposed at least partially about the first filling structure.
 4. Thesystem of claim 3, wherein the annular cuff is disposed about a neckregion of the filling structure.
 5. The system of claim 3, wherein thesealing feature comprises a thrombogenic material.
 6. The system ofclaim 5, wherein the thrombogenic material is selected from the groupconsisting of polyurethane, polycarbonate, polyester, ePTFE, polyolefin,parylene, gelatin and silicone.
 7. The system of claim 5, wherein thethrombogenic material comprises a thrombogenic drug.
 8. The system ofclaim 1, wherein the sealing feature comprises a frame coupled with aninside surface of the filling structure.
 9. The system of claim 8,wherein the frame comprises a resilient frame biased to flex radiallyoutward so as to facilitate outward expansion of the filling structureduring deployment.
 10. The system of claim 8, wherein the framecomprises any number of resilient metals and/or resilient polymers. 11.The system of claim 1, wherein the first filling structure has a mainbody with a main body width and the sealing feature comprises a narrowneck region coupled with the main body, the narrow neck region having awidth less than the main body width.
 12. The system of claim 11, whereinthe narrow neck region width is approximately 2% to approximately 20% ofthe main body width.
 13. The system of claim 1, wherein the sealingfeature comprises a tapered shoulder region on an upper portion of thefilling structure.
 14. The system of claim 13, wherein the taperedregion flares inwardly from the upper portion of the first fillingstructure to a lower portion of the first filling structure.
 15. Thesystem of claim 1, wherein the first filling structure comprises anupper layer of material and a lower layer of material, wherein at leasta portion of the upper layer is fixedly coupled with at least a portionof the lower layer of material, wherein the sealing feature comprises anupper filling region formed by a seal defining the upper filling regionand a lower filling region of the filling structure, the upper and lowerfilling regions in fluid communication with one another.
 16. The systemof claim 15, wherein the upper filling region holds a smaller volume offilling medium than the lower filling region.
 17. The system of claim 1,wherein the sealing feature comprises an arm in fluid communication withthe region filled with the hardenable filling medium.
 18. The system ofclaim 1, wherein the sealing feature comprises a cape or winged region,the cape or winged region flaring radially outward from the firstdouble-walled filling structure.
 19. The system of claim 1, wherein thesealing feature comprises a band extending circumferentially around thetubular lumen.
 20. The system of claim 1, wherein the sealing featurecomprises an enlarged head region and a tapered lower region of thefirst filling structure, the tapered region flaring radially outward asthe distance from the head region increases.